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dma-buf: Assign separate lockdep class to array lock

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dma_fence_array_enable_signaling() runs while holding the array
inline_lock and may add callbacks to underlying fences, which takes
their inline_lock.

Since both locks share the same lockdep class, this valid nesting
triggers a recursive locking warning. Assign a distinct lockdep class
to the array inline_lock so lockdep can correctly model the hierarchy.

Fixes: 5943243914 ("dma-buf: use inline lock for the dma-fence-array")
Cc: Christian König <christian.koenig@amd.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patch.msgid.link/20260224183922.2256492-2-matthew.brost@intel.com
This commit is contained in:
Matthew Brost
2026-02-25 01:19:41 -08:00
parent 2ec8653555
commit 2622649ad6
1 changed files with 14 additions and 0 deletions
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drivers/dma-buf/dma-fence-array.c
+14
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@@ -200,6 +200,8 @@ void dma_fence_array_init(struct dma_fence_array *array,
u64 context, unsigned seqno,
bool signal_on_any)
{
static struct lock_class_key dma_fence_array_lock_key;
WARN_ON(!num_fences || !fences);
array->num_fences = num_fences;
@@ -208,6 +210,18 @@ void dma_fence_array_init(struct dma_fence_array *array,
seqno);
init_irq_work(&array->work, irq_dma_fence_array_work);
/*
* dma_fence_array_enable_signaling() is invoked while holding
* array->base.inline_lock and may call dma_fence_add_callback()
* on the underlying fences, which takes their inline_lock.
*
* Since both locks share the same lockdep class, this legitimate
* nesting confuses lockdep and triggers a recursive locking
* warning. Assign a separate lockdep class to the array lock
* to model this hierarchy correctly.
*/
lockdep_set_class(&array->base.inline_lock, &dma_fence_array_lock_key);
atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
array->fences = fences;